In this study, we put an effort to estimate crustal depth and image crustal structure beneath Merapi volcano by employing multicomponent analysis popularly known as Receiver Function technique. We collected a series o...
In this study, we put an effort to estimate crustal depth and image crustal structure beneath Merapi volcano by employing multicomponent analysis popularly known as Receiver Function technique. We collected a series of waveforms from teleseismic events recorded from October 2013 to mid-April 2015 at 53 stations as a part of DOMERAPI project. We processed selected seismograms by simple deconvolution process between radial and vertical components to estimate the depth of Moho discontinuity beneath the volcano. Current results show complex structure beneath the volcano and a relatively potential Moho depth at about 30 km, which becomes shallower to the North at about 23 km. Stations located at Southern and Northern area show potential low velocity zone though a velocity modelling is necessary to confirm its depth and how low the velocity is.
The use of municipal solid waste as energy source can be a solution for Indonesia’s increasing energy demand. However, its high moisture content limits the use of solid waste as energy. Biodrying is a method of lower...
The use of municipal solid waste as energy source can be a solution for Indonesia’s increasing energy demand. However, its high moisture content limits the use of solid waste as energy. Biodrying is a method of lowering wastes’ moisture content using biological process. This study investigated the effect of wastes’ particle size variations on biodrying method. The experiment was performed on 3 lab-scale reactors with the same specifications. Organic wastes with the composition of 50% vegetable wastes and 50% garden wastes were used as substrates. The feedstock was manually shredded into 3 size variations, which were 10 – 40 mm, 50 – 80 mm, and 100 – 300 mm. The experiment lasted for 21 days. After 21 days, it was shown that the waste with the size of 100 – 300 mm has the lowest moisture content, which is 50.99%, and the volatile solids content is still 74.3% TS. This may be caused by the higher free air space of the reactor with the bigger sized substrate.
The quality of the higher education is the result of a continuous process. There are many indicators that can be used to assess the quality of a higher education. The existence of different indicators makes the differ...
The quality of the higher education is the result of a continuous process. There are many indicators that can be used to assess the quality of a higher education. The existence of different indicators makes the different result of university rankings. This research aims to find variables that can connect ranking indicators that are used by Indonesian Ministry of Research, Technology, and Higher Education with indicators that are used by international rankings by taking two kind of ranking systems i.e. Webometrics and 4icu. This research uses qualitative research method with comparative case studies approach. The result of the research shows that to bridge the indicators that are used by Indonesian Ministry or Research, Technology, and Higher Education with web-based ranking system like Webometrics and 4icu so that the Indonesian higher education institutions need to open access towards either scientific or non-scientific that are publicly used into web-based environment. One of the strategies that can be used to improve the openness and access towards scientific work of a university is by involving in open science and collaboration.
The concept of waste to energy emerges as an alternative solution to increasing waste generation and energy crisis. In the waste to energy concept, waste will be used to produce renewable energy through thermochemical...
The concept of waste to energy emerges as an alternative solution to increasing waste generation and energy crisis. In the waste to energy concept, waste will be used to produce renewable energy through thermochemical, biochemical, and physiochemical processes. In an anaerobic digester, organic matter brake-down due to anaerobic bacteria produces methane gas as energy source. The organic waste break-down is affected by various characteristics of waste components, such as organic matter content (C, N, O, H, P), solid contents (TS and VS), nutrients ratio (C/N), and pH. This research aims to analyze biodegradability and potential methane production (CH4) from organic waste largely available in Indonesia. Five solid wastes comprised of fecal sludge, cow rumen, goat farm waste, traditional market waste, and tofu dregs were analyzed which showed tofu dregs as waste with the highest rate of biodegradability compared to others since the tofu dregs do not contain any inhibitor which is lignin, have 2.7%VS, 14 C/N ratios and 97.3% organic matter. The highest cumulative methane production known as Biochemical Methane Potential was achieved by tofu dregs with volume of 77 ml during 30-day experiment which then followed by cow rumen, goat farm waste, and traditional market waste. Subsequently, methane productions were calculated through percentage of COD reduction, which showed the efficiency of 99.1% that indicates complete conversion of the high organic matter into methane.
Identifying distribution and stratigraphic of volcanic products are important not only for mitigating volcanic hazards, but also to know the characteristics of the successive eruptions. Guntur volcanic complex located...
Identifying distribution and stratigraphic of volcanic products are important not only for mitigating volcanic hazards, but also to know the characteristics of the successive eruptions. Guntur volcanic complex located in Garut, West Java, Indonesia was selected as study area because of the last eruption took place in 1847 and the volcanic activity has been dormant since then, however its seismicity is still active. During the period of July to October 2009, the hypocentre distribution of volcano tectonic earthquakes is mostly located at western flank of the volcano, beneath Guntur - Gandapura craters at the depth of less than 5 km. This study is aimed to identify distribution and succession of volcanic products based on their magnetic properties and backscattering signal of Polarimetric Synthetic Aperture Radar (PolSAR) data. The polarimetric decomposition method was used to identify the distribution of the volcanic products based on their scattering characteristics. Then, the field measurement using SM-30 magnetic susceptibility meter was performed to confirm the units of volcanic products and interpret their successions. According to the polarimetric decomposition method, we could identify fifteen successive eruptions formed Guntur Volcano Complex and termed as Khuluk and Gumuk in Indonesian standard. The successions were produced Gumuk Windu, Gumuk Malang, Gumuk Pulus, Gumuk Putrri, Khuluk Meungpeuk, Gumuk Cakra, Gumuk Gandapura, Gumuk Putri, Gumuk Gajah, Gumuk Batususun, Khuluk Pasirlaku, Gumuk Agung, Gumuk Picung, Gumuk Pasirmalang, Gumuk Masigit, Khuluk Kabuyutan and Khuluk Guntur. The magnetic susceptibility confirmed that the variations of magnetic susceptibility of rocks at each gumuk agreed with their stratigraphy.
The inadequate facilities and limited access to public transport reflect many people using private vehicles, in particular, motorcycle. The motorcycle is most widely used in Indonesia, recently, including Aceh Provinc...
The inadequate facilities and limited access to public transport reflect many people using private vehicles, in particular, motorcycle. The motorcycle is most widely used in Indonesia, recently, including Aceh Province. As a result, the number of motorcycle ownership is increasing significantly. The increasing number of motorcycles leads to complex traffic problems. Several factors tend to affect the trip generation of the motorcyclist, i.e., the social demographics of individuals and families, accessibility, etc. This study aims to analyze the characteristics of motorcyclists for non-mandatory activities, i.e. activities other than to work and school. It also aims to determine the dominant factors that affect their trips through trip generation models. The required data consist of primary data and secondary data. Primary data consists of a home interview survey that collects individual’s daily trips. It is conducted by distributing the questionnaires to 400 families residing in Lhokseumawe City. Modeling the trip generation of the motorcyclist is done by multiple linear regression analysis. Parameters calibration uses OLS (Ordinary Least Square) method. The results showed that the dominant variables that affect the trip generation of motorcyclist for non-mandatory activities are license ownership, housewife, school-age children, middle-income household, and lower education level. It can be concluded that some factors affecting trip generation to non-work activities were female motorcyclists from the middle-income household with lower education level. As their status is mostly as the housewife, escorting children to non-school activities seems to the mother’s task, instead of the father. It is clear that, most female ride motorcycle for doing household tasks. However, it should be noted that the use of the motorcycle in long-term does not suit for sustainable transportation.
Purpose of this research was to determine the contribution of student involvement in production/ service unit (X1), experience of industry practices (X2), and entrepreneurial attitude (Y) towards readiness entrepreneu...
Purpose of this research was to determine the contribution of student involvement in production/ service unit (X1), experience of industry practices (X2), and entrepreneurial attitude (Y) towards readiness entrepreneurship (Z) of vocational student regional Malang. The design of the study using a quantitative approach. The samples used as many as 130 respondents. Instruments used for collecting data in the form of questionnaires. Data analysis included descriptive and test of hypothesis. The result showed: that the description of data on the level of student involvement in production/ service unit, experience of industry practices, entrepreneurial attitude and entrepreneurship readiness in the high category. The contribution student involvement in production/ service unit of entrepreneurial attitude of 10.6%. The contribution experience of industry practices of entrepreneurial attitude of 17.4%. The contribution student involvement in production/ service unit and experience of industry practices simultaneously to entrepreneurial attitude of 44.1%. The contribution student involvement in production/ service unit of readiness entrepreneurship of 4%. The contribution experience of industry practices of readiness entrepreneurship of 5%. The contribution entrepreneurial attitude of readiness entrepreneurship of 16%. Finally, the contribution student involvement in production/ service unit, experience of industry practices, and entrepreneurial attitude simultaneously to readiness entrepreneurship of 50.3%.
Sanseviera trifasciata commonly called mother-in-law tongue also known as snake plant is native to Indonesia, India and Africa. Sansevieria is a new fiber in composite research and has showed promising properties as r...
Sanseviera trifasciata commonly called mother-in-law tongue also known as snake plant is native to Indonesia, India and Africa. Sansevieria is a new fiber in composite research and has showed promising properties as reinforcement material in polymer matrix composites. Chemical treatment on reinforcing fiber is crucial to reduce hydrophilic tendency and thus improve compatibility with the matrix. In this study, effect of maleic anhydride as chemical treatment on the mechanical properties of Sansevieria fiber/vinyl ester composite was investigated. Sansevieria fibers were immersed by using NaOH 3% for two hours at 100°C and then treated by using maleic anhydrate for two hours at 120°C. Composites were prepared by solution casting with various volume fractions of fiber; 0%, 2.5%, 5%, 7.5% and 10%. Actual density, volume fraction of void and mechanical properties of composite were conducted according to ASTM standard testing methods D792, D3171 and D3039. It was found that mechanical properties of composites increased as volume fractions of fiber was increased. The highest tensile strength and modulus of elasticity of composites were 57.45 MPa and 3.47 GPa respectively, obtained from composites with volume fraction of fiber 10%.
study the influence of high concentrations of antioxidants N-isopropyl-N-phenyl-p-phenylenediamine (IPPD) and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) and the mixing time of the vulcanization physical properties, th...
study the influence of high concentrations of antioxidants N-isopropyl-N-phenyl-p-phenylenediamine (IPPD) and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) and the mixing time of the vulcanization physical properties, thermal properties, mechanical properties and structure micro on natural rubber compound has been done. The purpose of this study is to compare the effect of anti-oxidants types IPPD and TMQ and mixing time of vulcanization of the physical properties, mechanical properties, microstructure and elemental composition of the synthesis of natural rubber compound. Processes of vulcanization with variations in the concentration of antioxidant IPPD and TMQ: 2, 3, and 4 grams and mixing time: 20, 30, and 40 minutes. Analysis characterization of physical properties and mechanical properties of natural rubber compound showed that the maturity value 0,499Nm (TMQ) and 0.489 Nm (IPPD), Mooney viscosity value of 26.7 (TMQ) and 20.8 (IPPD), the value of the elongation at break 583.75 % (IPPD), and 552.63% (TMQ) as well as the value of tensile strength of 28.108 *** (TMQ), and 27.986 *** (IPPD). Analysis of thermal properties of natural rubber compound antioxidant IPPD with DTA shows there are three endothermic peak on the curve that is temperature 405°C, 550°C and 660°C and tested by TGA showed that the curve of the total reduction in the sample are 81.745% and compound rubber antioxidant TMQ with the analysis of DTA also contained 3 endothermic peak at a temperature 397,21°C, 514,02°C, and 610,27°C and TGA analysis shows the curve of the total sample of 82.356% reduction. Gsi fun group analysis rubber-antioxidant compound IPPD / TMQ with FTIR spectrophotometer shows some typical infrared absorption peak at the wave number (1 / λ) 833-895 cm-1 for cluster / CH bonds, 1,313 cm-1 for group / single bond Si-O, 1368 cm-1 to g ugus / single bond CC, 1507 cm-1, for cluster / bond C = C, 1665 cm-1For cluster / bond-C = O, 2128 cm-1 is the group / bond CN single, 3371cm-1 for
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